While manual medicine can be a viable treatment option for musculoskeletal disorders such as low back or neck pain, the underlying mechanisms are largely unknown. Therefore, a critical barrier to advances in the disciplines of manual medicine is the need for scientific research focused on quantifying the efficacy and potential mechanisms related to treatment. Osteopathic manipulative treatment (OMT) is a complementary and alternative medicine (CAM) therapy which relies highly upon palpatory assessments during the physical examination to diagnose dysfunction of the neuromusculoskeletal system, including dysfunction of the spinal column. However, clinical assessments of this region have been controversial as the validity and reliability of such clinical tests are questionable. A Partnership for CAM Clinical Translational Research grant (PCCTR 1U19 AT00605701A1) has been awarded to Michigan State University (MSU) specifically to develop sensitive and reliable tools for quantifying therapeutic effects of OMT. Using a Systems Science framework, changes in the neuromuscular control parameters following OMT will be identified. This current application proposes an important supplement to this ongoing multi-project PCCTR grant by focusing on the neurophysiological mechanisms associated with the therapeutic effects of OMT for chronic neck pain. It is hypothesized that changes in the neuromuscular control parameters (e.g., feedback delays and gains) following OMT will be related to any combination of the changes in muscle reflex latency, force production, or recruitment pattern. To test this hypothesis, a battery of neurophysiological measures will be taken: 1) muscle short latency reflex response (amplitude and latency), 2) muscle isometric force production, 3) spinal muscle function using mfMRI, and 4) directionality of muscle activation using EMG. The relationship between these measures, neuromuscular control parameters obtained from the systems science approach and patient-oriented outcome measures will be determined. This project is organized around two Specific Aims: 1) To quantify differences in direct neurophysiological measures and patient-oriented outcome measures in chronic neck pain patients pre- and post-OMT and 2) To determine the relationship between direct neurophysiological measures, neuromuscular control parameters and patient-oriented outcome measures. These relationships will provide insight into the physiological mechanisms underlying the changes in neuromuscular control of the head-neck system following OMT. This overall post-doctoral training plan represents a rigorous, multi-disciplinary approach that utilize systems science framework to study complex systems. Better understanding of the complex interactions between direct neurophysiological measures, neuromuscular control parameters and patient-oriented outcome measures will provide insight into the mechanisms of OMT interventions.